There's a general rule in comics that characters rarely really change or grow. Batman and Superman will always be in their mid-30s. Everything in the Marvel universe will have happened in the last 10 years. This keeps things stable and simple and, in theory, easy for everyone to enjoy the stories.

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But some characters break this rule. They grow up and change and become something different. They move from the kids table to the adult table during the big superhero get-togethers and live it up as one of the big-time superheroes. What does it take to make it to the big leagues? How does a young hero get bumped up to the next level? There's no one answer to those questions, but here are 10 teen superheroes who graduated to the Avengers or Justice League...

Firestar is a rare character who got two promotions in her superhero career. She was created to act as the third hero in the classic animated series Spider-Man and His Amazing Friendsbut finally came to the Marvel Comics universe two years after the cartoon was canceled when she showed up in Uncanny X-Men #193.

Sometime later, Firestar would become a founding member of the New Warriors where comic fans would really get to know the character. When her New Warriors co-founder and boyfriend Justice decided to leave the team and try out for the Avengers, Firestar joined him. Both of the young heroes made the team.

Probably the most famous of all the superhero graduates, Wally West, the third Flash, went from pre-teen sidekick to founding member of the Teen Titans to founding member of the Justice League International offshootJustice League Europe before becoming a member of the Justice League proper.

For quite a while, Wally West stood out as the sidekick who made good on the promise. While other sidekicks have taken over for their mentors, Wally was the one who kept it going the longest, running for over 20 years before he got sent back down to the minors. Since then, DC has struggled to figure out what to do with the character, much to the chagrin of his fans.

Starting off as one of the Young Avengers, Hulkling is a KreeSkrull hybrid who uses his shapeshifting abilities to take on the characteristics of the original Hulk. As time went on, Hulkling started to become his own identity, thanks in part to his budding relationship with Wiccan. Hulkling started to use his powers to, among other things, grow wings and fly.

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After his time with the Young Avengers, Hulkling joined the New Avengers alongside Wiccan, Squirrel Girl, and a few other heroes. The team didn't last long, but Hulkling is plenty busy these days being the new ruler of the Kree-Skrull Alliance and helping plan the invasion of Earth for "the final war", which we'll all get to see in Marvel's upcoming Empyre event.

Growing up called "Night Boy" by his neighbors, Ray Terrill never left the house because of a deadly allergy to sunlight. At least, that was what he had been told. On his deathbed, Ray's dad reveals the truth; Ray was born with superpowers that are activated by the sun, but he couldn't control them. Now in his teens, Ray was ready to go out into the world and make a name for himself.

Taking a different path than most teen heroes, Ray skipped the lesser teams and was recruited into the Justice League when the team was looking to power up after the death of Superman. After about a year with the League, Ray left to join Young Justice and be with people his own age.

A founding member of the New Mutants, Roberto da Costa used his mutant abilities to absorb solar energy and turn it into a variety of powers like superstrength and solar blasts to help mutantdom. As Sunspot, Roberto has been a member of a number of teams, including X-Force and Young X-Men before becoming a member of the Avengers. Sunspot used his family's money to buy out A.I.M. and change it from the terrorist group Advanced Idea Mechanics to Avengers Idea Mechanics and forms his own Avengers team, New Avengers. After the New Avengers folded, Sunspot became the leader of U.S. Avengers.

Created by Geoff Johns and Lee Moder, Courtney Whitmore took on the superhero identity Star-Spangled Kid after learning that her stepfather was the original Star-Spangled Kid. Early into her career, Courtney joined the JSA and was gifted the cosmic staff by Starman when he decided to get out of the hero game. She changed her name to Stargirl and continued to make her mark as part of comics' first superhero team.

In the New 52 continuity, Stargirl joined the Justice League of America and was used as the face of this government back version of the classic team. After this iteration of Justice League of America dissolved, Stargirl joined Justice League United.

Created by Ultron, Victor Mancha grew up thinking he was a normal kid living a normal life with his normal single mother. He had no idea he was destined to become a supervillain called Victorious who would destroy the Avengers and rule the world in the near future. Thanks to the Runaways, Victor learned of his future and worked to make sure it would never come to pass.After the Age of Ultron event, Victor joined Hank Pym's Avengers A.I., a team that included Victor's "older brother" Vision, a Doombot, and Nick Fury's ex-wife, Monica Chang.

Originally a member of the Marv Wolfman and George Perez's New Teen Titans, Cyborg gained his cybernetic powers in a less than ideal way when he was caught in an explosion. To save his life, Cyborg's dad took what little of his son he could and transferred it to a robotic body powered by a Mother Box.

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While Cyborg was always a member of the Titans, he found himself being a part of the new Justice League after Doctor Manhattan had messed with the timestream, as seen in Doomsday Clock. He may have gotten the promotion in a weird way, but there's no doubt that Cyborg has the skills and powers that make him a good fit for the Justice League.

Just a high school student when he joined his sister, her fiance, and her fiance's college buddy for a trip into outer space in an experimental rocket ship, Johnny Storm became the Human Torch after being exposed to cosmic rays.

While he is first and foremost a member of Marvel's first superhero team, the Fantastic Four, he joined the Avengers for a time while Mister Fantastic and Invisible Woman were missing and presumed dead. Johnny had inherited the fortune of the Fantastic Four and used it to rebuild Avengers Mansion.

The first Robin, Dick Grayson not only gave birth to the kid sidekick concept, but he was also a founding member of the Teen Titans, acting as the team's leader for decades in the comics. Even when he gave up the Robin persona and became Nightwing, Dick stayed with his Titans teammates, but when he took over the Batman persona for the second time.

As with his first run as Batman, Dick didn't stay in the cape and cowl for long, and returned to the Titans when he went back to being Nightwing. Of all the grown-up sidekicks in the DC universe, Dick isn't the only one who should be on the Justice League, but he is the only one who has the skills needed to lead the team.

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Born and raised in New York, Derek Faraci moved to Los Angeles in 2001 where he worked as a freelance writer before taking a position at Activision where he worked on many successful franchises including Spider-Man, Tony Hawk and Guitar Hero.In October 2009, Derek left Activision to join Scientifically Proven Entertainment. Since joining SPE, Derek has worked on Man vs. Wild: The Game and the film Sucker directed by Michael Manasseri.Given the option, Derek would spend all of his time watching movies and reading comics.

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